This section provides background information related to the present disclosure which is not necessarily prior art.
FIG. 1 is a view illustrating one example of the semiconductor light emitting device (Lateral Chip) in the prior art, in which the semiconductor light emitting device includes a substrate 100, and a buffer layer 200, a first semiconductor layer 300 having a first conductivity, an active layer 400 for generating light via electron-hole recombination and a second semiconductor layer 500 having a second conductivity different from the first conductivity, which are deposited over the substrate 100 in the order mentioned, and additionally, a light-transmitting conductive film 600 for current spreading, and an electrode 700 serving as a bonding pad are formed thereon, and an electrode 800 serving as a bonding pad is formed on an etch-exposed portion of the first semiconductor layer 300. In this example, the side of the substrate 100 placed on the package serves as a mounting face.
FIG. 2 is a view illustrating another example of the semiconductor light emitting device (Flip Chip) in the prior art, in which the semiconductor light emitting device includes a substrate 100 (e.g. a sapphire substrate), and a first semiconductor layer 300 having a first conductivity (e.g. an n-type GaN layer), an active layer 400 for generating light via electron-hole recombination (e.g. InGaN/(In)GaN MQWs) and a second semiconductor layer 500 having a second conductivity different from the first conductivity (e.g. a p-type GaN layer), which are deposited over the substrate 100 in the order mentioned, and additionally, three-layered electrode films for reflecting light towards the substrate 100, i.e., an electrode film 901 (e.g. an Ag reflective film), an electrode film 902 (e.g., a Ni diffusion barrier) and an electrode film 903 (e.g. an Au bonding layer) are formed thereon, and an electrode 800 (e.g. a Cr/Ni/Au laminate metal pad) serving as a bonding pad is formed on an etch-exposed portion of the first semiconductor layer 300. In this example, the side of the electrode film 903 placed on the package serves as a mounting face. In terms of the heat dissipation efficiency, the flip chip shown in FIG. 2 or the junction down type chip demonstrates outstanding performances over the ones with the lateral chip shown in FIG. 1. This is because the lateral chip should dissipate heat outside through the sapphire substrate 100 with a thickness of 80 to 180 μm, while the flip chip can dissipate heat through the metallic electrodes 901, 902 and 903 placed near the active layer 400.
FIG. 15 is a view illustrating one example of a semiconductor light emitting device package or a semiconductor light emitting device structure in the prior art, in which the semiconductor light emitting device package is provided with lead frames 110 and 120, a mold 130, and a vertical type light-emitting chip 150 in a cavity 140 which is filled with an encapsulating material 170 containing a phosphor 160. The bottom face of the vertical type light-emitting chip 150 is electrically connected to the lead frame 110, and the top face thereof is electrically connected to the lead frame 120. A portion of the light (e.g., blue light) emitting from the vertical type light-emitting chip 150 excites the phosphor 160 such that light (e.g. yellow light) is generated by the phosphor 160, and these lights (blue light+yellow light) produce white light. In this example, the mold 130—the encapsulating material 170, or the lead frame 110 and 120—the mold 130—the encapsulating material 170 serve as a support, that is, a carrier, for the semiconductor light emitting device package, while supporting the vertical semiconductor device.
FIG. 54 is a view illustrating one example of the semiconductor light emitting device (Flip Chip) described in JP Laid-Open Publication No. 2006-120913, in which the semiconductor light emitting device is of a flip chip type employing an insulating film 910 and a metal film 920, instead of the electrodes 901, 902 and 903 as in the semiconductor light emitting device shown in FIG. 2. The light L generated in the active layer 300 is usually reflected from the insulating film 910 and then reflected towards the first semiconductor layer 300 or the substrate 100. A portion of the light L is reflected from the metal film 920. Preferably, the insulating film 910 has a DBR. Any description of the same reference numerals will not be repeated.
FIG. 55 is a view illustrating one example of the semiconductor light emitting device (Flip Chip) described in JP Laid-Open Publication No. 2009-164423. This semiconductor light emitting device differs from the one shown in FIG. 54 in that the former is configured to have holes 910h in the insulating film 910 such the metal film 920 supplies current to the semiconductor light emitting device through a light-transmitting conductive film 600, while in the latter current is supplied through the electrode 700. Preferably, the insulating film 910 has a DBR, and is formed across the entire semiconductor light emitting device as well as on an etch-exposed portion of the first semiconductor layer 300. In addition, the metal film 920 is formed on the etch-exposed portion of the first semiconductor layer 300.